Last fuel stop before airport

Question

This morning I returned a rental car to LHR T5. I'm approaching along the M25 and am looking for petrol stations along the way and, as usual, I don't find one. I look on my iphone for fuel and it gives me a load of useless petrol stations all over the countryside which are no use to anybody.

I've been in this situation at T5 a few times and I know a place to go, but it's always annoying. What I'm looking for is an app for iphone or android, or perhaps a web service, that tells me the last fuel stop on my route to the airport before I return a rental car, or if there isn't one, the one closest to the airport after arriving. Surely lots of people would find this useful?

I don't want the nearest to me, or the nearest to the airport, but the nearest to the airport on my route to the airport. Does such an app exist? I rent cars in various countries mainly in Europe and the US, so ideally something generic.

I swear the rental car companies are in collusion with others to prevent you knowing where to fill up so that you end up having to pay outrageous refueling charges.

Edit: As suggested in comments, maybe it should show the best place to refuel, based on price and/or distance from airport.

The "best" place depends on various criteria. If you're in a hurry, or your fuel is on expenses, you might not care for optimising for the lowest price. If you're paying yourself and time isn't of the essence, then maybe you're willing to take a small diversion.

I signed up to petrolprices.com as someone mentioned it in the comments. For LGW, the most convenient petrol station for most people arriving from the M23 would be the Gatwick South BP station at 115.9p/l

A search centered on the airport shows cheaper petrol stations:

Heading to Heathrow T5 is more complicated. There are no petrol stations approaching on the M25, and some of the ones on the map require non-simple diversions depending on whether you are approaching from the North or South:

I had a quick look at google maps on the iphone and waze. Waze is a bit annoying in that it expects me to enable location monitoring 24/7 and won't let me search for anything useful until I've become some sort of qualified member.

Google maps didn't show me petrol stations in Rome that I would have chosen on the way to the airport, so I'm not convinced it's doing a great job either.

Further info supplied in comments (thanks @Freeman, @user1908704, @JonathanReez, @CMaster, @others):

Related TSE QA.

Waze:

Waze differs from traditional GPS navigation software in that it is community-driven, gathering complementary map data and traffic information from its users. Like other GPS software it learns from users' driving times to provide routing and real-time traffic updates. It is free to download and use. People can report accidents, traffic jams, speed and police traps, and from the online map editor, can update roads, landmarks, house numbers, etc. Waze also identifies the cheapest fuel station near a user or along their route, provided Waze has enabled gas prices for that country.

Which sounds like it should do what is necessary if someone can explain how, ideally with a few screenshots and examples.

Roadtrippers:

Our unique content covers the wonderful "off the beaten path" places to visit and our unique database contains millions of the world's most interesting locations. Roadtrippers helps people discover the world around them in an entirely new way by streamlining discovery, planning, booking and navigation into an engaging and intuitive process

Rental car companies typically suggest you should fill up within 10 miles of returning the car, so although probably not all that significant, refueling 10 miles before return might be more optimal than 1 mile before return, given that the cost of fuel right next to the airport is probably higher than 10 miles away also.

Fuel price sites/apps:

• petrolprices

Our site allows users to search for the cheapest petrol in their area quickly and, if they choose, receive regular alerts so they will always be the first to know when the prices change.

• gasbuddy

GasBuddy.com is a group of local websites which offers an online method for website visitors to post and view recent retail gasoline prices.

Answer 1

In Google Maps, while using the App to get directed for example to rental car return, you can search for locations 'on the way'. If you click 'Gas Stations', it shows gas stations along the way, with the amount of time the detour forces, and with their gas price (if known).

It does not automatically select or offer the last possible one as you asked, but it is easy to see which one that would be. Also, you might want to take the next-to-last if it is significantly cheaper or only a 2-minute detour, and the last one would be a 15 minute detour.

Edit: you can use the functionality for planning by just acting as if you are doing the drive now (ignoring the voice directions), and then changing the zoom/view to the area that you are interested in. It will update the search for the selected area. Example: you sit in Munich, but you want to see the gas stations just before London Heathrow, for a trip next month. Use the app to get directions to Heathrow, then search for gas stations along the way. First, it will come up with gas stations near Munich, as that's where you are. Move/zoom the map to Heathrow, and the display will update with gas stations around Heathrow.

I use that all the time when returning rentals (and also in normal life when in unfamiliar areas), it works very well.

Regarding the tip some people gave - it is common that cars show the tank as 'full' for the first 20 to 40 miles (30 to 60 km) after filling, and many people take advantage of that - fill up 20 miles before the return point, and it will still show 'full' when you return the car.

Answer 2

I don't know about the UK, but in the US there are several apps like GasBuddy which specifically list fuel stations. While they're not sufficiently specific to show 'last stop' only, if you simply search for the airport or somewhere nearby and then look on the map, it will show you all fuel stations nearby - and then you can pick whichever is convenient to your route. They tend to do a much more thorough job than a Google search of showing fuel stations, and they show you prices (based on user input; GasBuddy is almost always updated within a day or so no matter where I've tried it).